I generally avoid using mayonnaise in my sushi rolls, but the sweetness of Japanese mayo with the texture of the grated cucumber and herbaceous shiso pairs nicely with the Dungeness crab. Plus it's brightened by the lemon juice. The avocado adds a bit of creaminess to the roll and the cucumber sticks give a nice crunch. It's a twist on the American sushi classic—the California roll—and it's bound to please sushi novices and aficionados alike.
For the shiso mayo: Stir together the mayonnaise, shiso and cucumber in a small bowl. Cover and refrigerate until ready to use.
For the roll: Gently squeeze the crabmeat to drain out any excess moisture and place in a medium bowl. Add the lemon juice, mix and set aside.
Lay a half nori sheet textured-side up (smooth/shiny-side down) on a cutting board with one of the longer sides closest to you. Moisten your fingers with ice water and gently spread 1/2 cup of the prepared sushi rice evenly over most of the nori, leaving a 1-inch strip without rice on one short edge. Rotate the nori so the short edge with rice is closest to you.
Place 1 1/2 ounces of crab in a line across the rice. Lay 2 pieces of avocado next to the crab. Lay 3 to 4 pieces of cucumber on top of the avocado slices. Make sure your roll fillings are evenly distributed across the roll—all the way to each edge. Slip your thumbs under the near edge of the nori and roll the sushi roll away from you with gentle pressure until the edge without sushi rice is on the bottom creating a seam.
Dip the tip of a knife into the ice water and allow the water to run down the blade. Slice the sushi roll into 6 even pieces. Repeat with the remaining ingredients, making 4 rolls.
Spoon some shiso mayo over the top of the sushi rolls and garnish each with 1/4 to 1/2 teaspoon sesame seeds if desired. Serve with soy sauce, ginger and wasabi if desired.
If using regular mayonnaise, such as Best Foods brand, add 1 teaspoon granulated sugar.
The shiso leaves can be substituted with 1 teaspoon of finely chopped fresh mint.
Make sure your roll fillings are evenly distributed across the roll—all the way to each edge.